How to Balance Your Hormones and Improve Your Energy Through Circadian Rhythm Fasting

People sitting on a blanket in a field with bicycles and a basket of fruit for circadian rhythm fasting

You’ve probably heard the saying, “You are what you eat.”

But what if that only paints part of the picture? What if when you eat is just as important as what you eat?

Let’s take it one step further, though. Timing your meals with your body’s internal clock – known as circadian rhythm fasting – may provide some serious health benefits.

In this article, we’ll dive into what circadian rhythm fasting is, how it might help balance your hormones and boost your energy, and how you can adopt it in your daily life.

What is the Circadian Rhythm?

Before we dive into circadian rhythm fasting, let’s talk about the circadian rhythm.

Although often called your “sleep-wake cycle,” your circadian rhythms regulate much more than your alertness or sleepiness. It refers to just about any physical, mental, or behavioral changes that repeat on a 24-hour cycle and help you adapt to your changing environment.

Your circadian rhythms are generated by a “master clock,” which is actually a group of nerve cells in your brain that forms a structure called the suprachiasmatic nucleus (SCN). In addition to your sleep-wake cycle, the master clock influences the following:>

  • Body temperature
  • Urine production
  • Blood pressure
  • Heart rate
  • Appetite
  • Stomach and bowel function
  • Mood
  • Hormone balance

The master clock in your SCN works with the other internal clocks to keep your body running optimally. And to do so, your body’s clocks take cues from your external environment, the most powerful of which is light.1 Another major factor is feeding time.2 Others include temperature, physical activity, stress, and social environment.3

But sometimes, we can provide the wrong cues or the right cues at the wrong time, leading to our circadian rhythms falling out of sync with the outside world. This may include (but is not limited to) things like traveling between time zones or light from electronic devices at night.

Chronic circadian rhythm disruption has been linked to many negative health consequences, such as:

In fact, the International Agency for Research on Cancer has classified night shift work as a “probable carcinogen” due to its disruption of normal physiological circadian rhythms.10

What is Circadian Rhythm Fasting?

Circadian rhythm fasting is a form of time-restricted feeding that encourages you to time your meals with the rise and fall of the sun.

But why is this important?

Your circadian clocks also play a role in producing and regulating certain hormones. Some of these hormones depend on the SCN rhythmic activity (which responds to light and darkness), while others fluctuate based on both the circadian rhythm and feeding/fasting cycles.11

Let’s go into a bit more detail. Human physiology is adapted to two 12-hour phases: an activity phase that begins at 10 a.m. and ends at 10 p.m., and a resting phase which starts when the activity phase ends.12 These phases depend on the hormone melatonin.

Melatonin, often called the “sleeping hormone,” plays a central role in regulating your circadian rhythms by relaying information regarding the environmental light-dark cycle. Secretion of melatonin begins around 10 p.m. and peaks around 3 a.m.13

The hormone that plays the role opposite of melatonin is cortisol. As melatonin secretion is winding down, cortisol begins to rise, peaking between 7 a.m. and 8 a.m. in healthy individuals.14 This is in line with the need to prepare your body for the day’s energetic demands. Cortisol also regulates your metabolism, which means your body can effectively convert what you eat into energy.

Nutrient-sensitive hormones, such as ghrelin, adiponectin, insulin, and leptin, also largely follow your circadian rhythms and are regulated, at least in part, by environmental stimuli.

Given that these hormones are essential to physiological processes at certain times of the day, many experts agree that the optimal time for food intake is daytime.15

Circadian Rhythm Fasting vs. Intermittent Fasting: What’s the Difference?

Time-restricted eating is a type of intermittent fasting. But time-restricted eating methods like circadian rhythm fasting differs from intermittent fasting in three main aspects:

  1. Time-restricted feeding does not require caloric restriction.
  2. It requires a consistent daily eating window. In circadian rhythm fasting, this means aligning your eating hours with your natural circadian rhythm. Intermittent fasting allows you to determine your own eating schedule.
  3. Since circadian rhythms are divided into two 12-hour windows, you’ll be required to fast for at least 12 hours overnight. The fasting window can be extended to 16 hours if desired.

Circadian Rhythm Fasting Benefits

Recent research studies have shown that time-restricted feeding can play a crucial role in maintaining good health. A few known benefits include:

  • Lower systemic inflammation, which reduces your risk of inflammatory and metabolic diseases16
  • Improved energy17
  • Stronger immune system18
  • Weight loss and fat loss19
  • Better mood20
  • Healthier aging21
  • Improved cardiometabolic measures, such as insulin sensitivity and blood pressure22
  • Better digestion and overall gut health23,24

Growing evidence shows the strong link between the circadian clock, hormonal balance, and energy metabolism. For example, one study involving human subjects found that a sleep-wake misalignment caused decreased leptin, increased glucose despite increased insulin, and a complete reversal in daily cortisol rhythm.25

Following a strict circadian rhythm fasting regimen may also positively affect your gut microbiome. Results from animal studies suggest that circadian rhythm fasting positively affects gut microbial community structure. In one study, circadian rhythm fasting reduced the abundance of Lactobacillus and Lactococcus species, some of which are associated with obesity. Conversely, there was an increase in the levels of Ocscillibacter and Ruminococcaceae species, which have a protective effect against obesity and metabolic diseases.26

Researchers have also found that approximately 60% of the gut microbiome composition oscillates over a 24-hour period. Functions such as energy metabolism, DNA repair, and cell growth are best performed during the “resting phase,” while those involving detoxification, motility, and environmental sensing are optimally performed in the “activity phase.”27 As you can imagine, chronic disruptions to your sleep-wake cycle can negatively affect these essential functions, leading to health issues such as chronic inflammation.

That’s why it’s now more important than ever to sync your lifestyle – including your mealtimes – with your circadian rhythms.

How To Adopt Circadian Rhythm Fasting in Your Daily Life

Ready to give circadian rhythm fasting a try? Here are some practical tips to get started.

  • Implement time-restricted eating to synchronize eating patterns with your body’s natural rhythms: Ideally, you should eat breakfast within 2 hours of waking up, and no later than 10 a.m. Your last meal of the day should be no later than 6 or 7 p.m. Yes, this means no late-night snacking. Shorter daylight hours during the winter months can make this more difficult. In this case, you can just keep the majority of your meals during the day so that you can still support your circadian rhythm.
  • Incorporate nutrient-dense foods that support hormonal health into your diet: Circadian rhythm fasting doesn’t specify which foods are off-limits. However, it’s a good idea to prioritize nutrient-dense foods, such as those high in fiber, protein, and healthy fats.
  • Follow a consistent sleep schedule: Maintaining a consistent sleep schedule – yes, even on the weekends – is one of the best ways to keep your circadian rhythms in check. It helps you feel sleepy at the same time every day and may improve your sleep quality.
  • Get plenty of light during the day: Light is the most powerful regulator of your body’s internal clocks. Therefore, it’s especially crucial to get bright light exposure in the first hour or two after waking. Bright light also promotes alertness, which may help you get started on your day.
  • Avoid using light-emitting electronic devices at night: If getting enough light is important upon waking up, darkness is equally important when going to sleep. The best sleep environment is an area that is cool, dark, and quiet.28 Electronic devices emitting blue light should be avoided for at least 1 hour before bedtime. Light exposure suppresses melatonin, so a dark environment will allow your body to naturally produce melatonin and prepare for sleep.
  • Manage stress through techniques like meditation or exercise: The impact of stress on hormonal balance cannot be emphasized enough. Research studies suggest that chronic stress can cause strong phase shifts of other internal clocks in your body, such as those of the liver, kidney, and heart. When such desynchronizations happen, they can throw off the precisely orchestrated physiological and behavioral processes in your body, leading to negative health consequences.29 One of the best ways to manage stress is through meditation or exercise. I especially recommend strength training to build or maintain muscle mass as you age.

Live in Harmony With Your Circadian Rhythm With a Women’s Hormone Specialist in Boston

There is no way to overstate the importance of living in sync with your circadian rhythms.

But lifestyle changes can be overwhelming. There’s so much information out there, and many people give up simply because they find navigating through it all difficult.

With the proper guidance, you don’t have to be yet another statistic, adding to the number of people who give up on their New Year’s resolutions.

As a women’s hormone specialist, I’m passionate about helping women optimize their lives and well-being through natural, practical methods.

Want to work with me? I offer 15-minute complimentary consultations to women all across the world. I look forward to hearing from you soon.



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